MYST: The MYST family, which was named after the initials of the founding members: MOZ, Ybf2/Sas3, Sas2, and Tip60, is the largest family of acetyltransferases with diverse biological functions. In the budding yeast, Esa1 of the NuA4 complex is known to be an essential HAT required for DNA repair and cell cycle progression. In animal systems, the role of MYST family HATs in stem cells, development and cancer have been thoroughly documented. It is of note that MYST family HAT complexes are known to have the broadest range of substrates including non-histone targets. The regulatory role and the ubiquity of protein acetylation had long been suspected to be comparable that of phosphorylation. (1)